Fin mounting system

ABSTRACT

A system for removably mounting fins to a water craft or surfboard comprising drilling one or more cavities completely through the water craft or surfboard, inserting a sleeve in each cavity, filling the void between the sleeve and the cavity with a thermosetting resin which binds the sleeve in the cavity, inserting a fin having one or more footings into sleeves, each footing frictionally fitting into a sleeve.

This invention is described in my Provisional Patent Application filed on Jun. 2, 2004, bearing application No. 60/576,174.

BACKGROUND OF THE INVENTION

This invention relates to a system for removably mounting fins to a surfboard or other type of water craft. Typically from one to five fins are mounted to the base of a surfboard either permanently, by creating a resin fillet around the base of the fin, or removably by setting a fin box, plug or other such element, in the board body. All of the existing methods of attachment have significant disadvantages to both manufacturer and consumer.

Permanent mounting of fins to a board is a labor intensive and costly process for the manufacturer. Further, after the fins are mounted to the board, the finished product is bulky and requires substantial storage space, further increasing overhead.

Fin size and shape are known to significantly affect the performance of the board. Permanently mounted fins prevent the consumer from altering board performance, by changing fins, to adapt to a variety of ocean conditions. In addition, permanent fin mounting is a burden to the consumer and manufacturer during transport, as many carriers charge per package, and the bulk of permanently mounted fins limits the number of boards that can be placed in any one package. In addition, boards with permanently mounted fins are more frequently damaged during transport because the fins protrude from the board surface.

Removably mounted fins alleviate many of the problems described above simply by providing removability. However, the performance of removably mounted fins is inferior to permanently mounted fins. Removably mounted fins, as presently manufactured, are often quite difficult to install.

The strength of removably mounted fins, as compared to that of permanently mounted fins, is much less because the current technology relies on a structural bond between the box, plug or other such element and the setting resin, which is insufficient. Further, the box, plug or other such element is typically set, such that lateral load on the fin results in crushing of the foam board body. It is common for removably mounted fins to loosen or fall out as a result of normal use.

Removably mounted fins require a fastening element, which is traditionally tapped through the fin box, plug or other such element. It is common for the fastening element to strip as a result of excessive torque during fastening, requiring a laborious removal of the embedded box, plug or other such element. In some instances, access to the fastening element is only possible through the deck of the board, the surface, opposite the fins, upon which the rider stands, preventing use of a conventional adhesive traction pad.

Fin flex and stiffness is known to significantly affect the performance of the board. Removably mounted fins do not provide the same drive or holding power as permanently mounted fins. In current practice, removably mounted fins are fastened inside or at the fin face which, even when tightly fastened, allows for rotation and prevents true fixity, as is found in a permanently attached fin, from being achieved. Also, the element extending from the fin base into the fin box, plug or other such element, is frequently not as stiff as the fin itself, resulting in additional loss of stiffness.

Fins are traditionally mounted at a slight angle, relative to the perpendicular that intersects the plane of the assumed flat board surface. Use of removably mounted fins for such application requires additional labor as the planar surface of the box, plug or other such element protrudes from the plane of the board surface and must be removed by sanding or grinding. The problem is magnified when the board has a contoured bottom, which often times is significant enough to prevent the use of removably mounted fins.

SUMMARY OF THE INVENTION

The present invention comprises a removably mounted fin system, utilizing molded thermoplastic, tubular sleeves embedded in the board body, which receive footings extending from the fin base. The tubular sleeves are sealed at one end to prevent resin from entering the sleeves during mounting. The footings may be fixed by means of a fastening element tapped through the fin footing.

The primary advantage of the present invention is that it allows the fin to be mounted with true fixity, eliminating rotation at the fin base, providing increased stiffness and desirable flexure, which all serve to enhance fin performance. This advantage is realized by the fin footing, which protrudes significantly outward from the fin face.

Another advantage of the present invention is that it does not rely on a structural bond between the element embedded in the board body and the setting resin, and normal usage will not cause foam crushing at the interface between the embedded element and the foam board body, and as a result the connection is significantly stronger than exists in the prior art. This advantage is realized by the load transfer system configuration of the tubular sleeve outer wall.

Another advantage of the present invention is that the fastening element is tapped through the fin footing rather than the fin box, plug or other such element, so that failure of the fastening element is easily remedied. This advantage is best realized by the fact that the fastening element is not tapped through any element that is permanently set in the board. A second advantage to fastening through the footing is that access through the board deck is not required and a conventional adhesive traction pad may be used.

Another advantage of the present invention is that the significant lateral loads occasioned by normal usage are not transferred through the fastening element, but rather directly to the tubular sleeve body such that greater fixity is achieved. This feature is best realized by the fact that the optional fastening element runs longitudinally and is used only to resist pullout forces.

Yet another advantage of the present invention is that it may be mounted in a board with any reasonable contour and requires far less labor than the prior art when mounted at an angle. This advantage is best realized by the fact that the tubular sleeve has no planar surface in the plane of the board.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side section through the fin centerline.

FIG. 2 is a section through the fin body looking forward.

FIG. 3 a is a fin detail showing a side elevation,

FIG. 3 b is a front elevation,

FIG. 3 c is a plan view,

FIG. 4 a is a tubular sleeve detail plan view,

FIG. 4 b is a side sectional view,

FIG. 5 is a fragmentary plan view showing tubular sleeves set in the board body.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring now to the drawings, there is shown a fin 10, mounted to the base 40 of surfboard 12, or other type of water craft, using a plurality of tubular sleeves 14 a and 14 b embedded within the board body 12. Tubular sleeves 14 a and 14 b each receive a footing 16 a and 16 b, extending from the base 18 of fin 10.

The mounting of fin 10 is achieved by cutting oversized through cavities or holes 20 a and 20 b in board body 12, inserting or placing sleeves 14 a and 14 b inside of through cavities 20 a and 20 b, adjusting sleeves 14 a and 14 b, as required to obtain the optimum fin position, and then filling the void between sleeves 14 a and 14 b and the cavity 20 a and 20 b side walls with a thermosetting resin 22, which binds each sleeve in each cavity.

An optional fastening element 32 running longitudinally through fin footing 16 b and bearing against sleeve 14 b is used, in conjunction with friction, to fix fin 10 in position, allowing for removal or replacement of fin 10 as desired.

Footings 16 a and 16 b are comparatively stiffer than the base 18 of fin 10 itself, which allows fin 10 to take on a desired deformed shape. Footings 16 a and 16 b laterally engage tubular sleeves 14 a and 14 b, outside the face 26 of fin 10, preventing rotation of fin base 18. Footings 16 a and 16 b have a textured or free form outer surface 30 a and 30 b, which makes a stronger frictional fit in sleeves 14 a and 14 b. While two footings are preferably shown for each fin, one or more footings may be utilized.

Sleeves 14 a and 14 b, which are constructed from a molded thermoplastic material, have a textured or threaded outer surface 28 a and 28 b, which provides a stronger connection with the resin than a smooth surface would. Fin 10 is constructed from a molded thermoplastic composite material or from glass fiber reinforced polyester resin.

Sleeves 14 a and 14 b are capped at the lower end 38 a and 38 b (see FIG. 1). However, optionally, a hole 24 can be drilled through base 38 a and 38 b of sleeve 14 a and 14 b and the board top lamination layer 36, which is useful to get a stuck fin footing out of its sleeve. There is also a laminate layer 34 on the bottom of board 12.

Having thus described the invention, 

1. A water craft having a base and one or more removable fins depending therefrom, each fin having one or more footings, comprising a cavity through the water craft for each footing, a sleeve in each cavity, a thermoplastic resin binding each sleeve in each cavity, each footing frictionally held in each sleeve.
 2. The device of claim 1 in which the water craft is a surfboard and a plurality of removable fins depending therefrom, each fin having two or more footings, comprising a hole for each footing passing completely through the surfboard, a sleeve in each hole, a thermoplastic resin binding each sleeve in each hole, each footing frictionally held in each sleeve.
 3. The device of claims 1 or 2, in which each sleeve has a textured outer surface.
 4. The device of claims 1 or 2, in which a fastening element runs longitudinally through either footing against either sleeve.
 5. The device of claims 1 or 2, in which each footing has textured outer surface.
 6. The device of claims 1 or 2, in which the sleeves are capped at one end.
 7. The device of claims 1 or 2, in which the sleeves are made from a molded thermoplastic material.
 8. The device of claims 1 or 2, in which the fin or fins are made from a molded thermoplastic material or a glass fiber reinforced polyester resin.
 9. The device of claims 1, 2, in which the sleeves are capped at one end and have a hole drilled through each cap.
 10. The device of claims 1 or 2, in which the water craft or surfboard is laminated on one or both the top and bottom surface.
 11. A method for removably mounting a fin onto the base of a water craft or surfboard comprising cutting one or more cavities completely through the water craft or surfboard, inserting a sleeve in each cavity, filling the void between the sleeve and the cavity with a thermosetting resin which binds each sleeve in a cavity, inserting a fin having one or more footings into sleeves, each footing frictionally fitting into a sleeve.
 12. The method of claim 1 1, further comprising placing a fastening element longitudinally through one footing of each fin against the sleeve.
 13. The method of claim 11, in which each sleeve has a textured outer surface.
 14. The method of claim 11, in which each footing has a textured outer surface.
 15. The method of claim 11, in which the cavities are placed in the water craft or surfboard at locations which result in the fins being set for maximum performance of the water craft or surfboard.
 16. The method of claim 11, in which each sleeve is capped at one end.
 17. The method of claim 16 further comprising drilling a hole through each capped sleeve.
 18. The device of claims 1 or 2 in which the footings laterally engage the sleeves outside the fin face. 